1. Field of the Invention
This invention relates to endosseous dental implants. More particularly this invention relates to a combination osteointegrated dental implant and trephine which is placed using a one-step surgical technique.
2. Description of the Prior Art
Endosseous dental implants were first attempted in the early part of this century. Today a variety of implant designs are in widespread use in the dental arts, including hollow, self-tapping screws with sluices, hollow basket implants, Vent-Plant designs, and many others. These designs, combined with modern biomaterial science, have as their object the promotion of rapid osteointegration to stabilize the implant within the bone.
The development of these dental implants has been fraught with difficulties. With some designs an interfacial fibrous tissue reaction tends to encapsulate the implant and prevent the ingrowth of trabecular bone. It has been found that the techniques used with certain implants risk the formation of epithelial inclusions. Still other designs have relatively wide flanges that increase the surface area in apposition with bone, but have poor tolerance for misalignment and risk maxillary or palatal bone perforation. Crushing and devitalization of bone adjacent the implant during repeated instrumentation of the implant site is yet another well known problem, and is sought to be avoided by implant designs having a generally open apical architecture that lessens intraoperative hydrostatic pressure and encourages blood supply to the chamber of the implant.
Conventionally, preparation of a bed for hollow cylinder implants requires several manipulatory steps, each of which traumatizes the bone and adversely affects the healing process. After reflection of a mucoperiosteal flap, a burring step, usually conducted with a round burr, marks the implant site. The cortical bone of the alveolar crest is then pre-drilled at slow speed and under copious irrigation with chilled saline to expose the underlying cancellous bone. A trephine is then used to mill the cancellous bone and form a bed having a desired depth. The bed must be probed to confirm its depth. Only then can the implant be inserted by a hollow threaded screw or press-fitted. Variants of the above-described procedure are known, but all involve substantial insult to the bony structures that tends to impair healing and bone regeneration. Furthermore the repeated surgical instrumentation of exposed bone risks overheating of the bone, possible misalignment of the prepared site, the introduction of bacteria into the wound and the development of infection that could retard wound healing or result in failure of the implant.